Calculations

Calculations

Applying calculations to your visualization helps further customize, filter, and aggregate data. Calculations can be something as simple as applying an AVG (average) or any other aggregate function.

Regardless of what type of calculation you apply to your visualization, we consider the result a calculated field.

When a new calculation is created, a new pill will be added to your data pane under the name you provided the calculation. We will cover basic calculations and table calculations below.

Basic Calculations

Basic calculations in Tableau revolve around using arithmetic operators and functions to manipulate and transform your data as you see fit. Calculations can be applied to an individual field or multiple fields, allowing you to create new extracted fields based on your analysis requirements.

Take a look at the example below:

AVG([Transaction Total])

Calculation Components

When you are creating a new calculation there are multiple components to familiarize yourself with:

1. Fields: You are able to include existing fields from your data inside of a calculation, like in the example above referencing the Transaction Total field.
2. Operators: (>, <, =, >=, <= etc..)
3. Literal expressions: Specific values (23, "String", true, false, null, #Date)
4. Functions: Tableau provides a large number of functions that you can apply within your calculated fields. The functions available include aggregate functions, number functions, logical functions, etc..

While creating a new calculated field, you can select or include a function from a list.

1. Click on Analysis.
2. Then click on Create Calculated Field....
3. Click on the arrow to expand the list of available functions.

Table Calculations

Table calculations in Tableau are a powerful tool for performing calculations on data within a visualization, based on the context of the table or chart. They allow you to create dynamic and informative visualizations which provide insights into your data that would be difficult or impossible to achieve with simple calculations.

Here are a few key concepts to be familiar with in creating table calculations:

• Addressing: Determines the direction in which the calculation is performed. For example, across rows, down columns, or across a specific dimension.
• Partitioning: Defines the groups or subsets of data within which the calculation is applied. This allows you to perform calculations on specific segments of your data.
• Compute Using: Specifies the field or fields that determine the calculation’s scope and direction.

There are several common table calculation functions immediately available within Tableau:

• Running Totals: Accumulate values over time or across categories.
• Differences: Calculate the difference between values in adjacent rows or columns.
• Percentages: Calculate percentages of totals or grand totals.
• Moving Averages: Calculate averages over a specific window of data.
• Rank: Rank values within a group or partition.
• Custom Calculations: Create your own calculations using Tableau’s built-in functions and operators.

To add a table calculation to a visualization within Tableau:

1. Build your basic visualization using your desired dimension(s) and measure(s).
2. Right-click on the measure you want to calculate and select “Quick Table Calculation” or “Edit Table Calculation.”
3. Select the desired calculation type from the options provided.
4. Adjust the addressing, partitioning, and compute using settings to customize the calculation.

Filling in the Gaps: PluralSight Content (see warning notice below)

At this moment, please pause your reading of the textbook and complete the two PluralSight learning modules linked below. These modules will help you further understand how to use calculations and quick table functions in Tableau. Once you are finished with these modules, please resume reading this chapter.

1. Introduction to Calculations in Tableau
2. Numerical Calculations and Quick Table Functions

Partitioning Fields

When working with table calculations, you can optionally specify one or more partitioning fields. Partitioning fields are used to define subsets or partitions of your data, and the table calculation will be performed independently for each partition.

Addressing Fields

In addition to partitioning fields, table calculations also require you to specify one or more addressing fields. Addressing fields determine the order or direction in which the calculation is performed within each partition.

Conditional Statements

You can utilize a few types of conditional statements within calculated fields. The three types of conditional statements we will cover are IF, IIF, and CASE statements.

IF some condition
THEN do this
## ELSE statement is optional
ELSE do this
END

IIF (some condition, do this if true, else this if false, handle unknown)

CASE[Operating Systems]
WHEN 1 THEN "Linux"
WHEN 2 THEN "Windows"
WHEN 3 THEN "MacOs"
END

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